1.Field of the Invention
The present invention relates to a photosensitive material automatic-processing apparatus in which at the time of processing a photosensitive material having a photosensitive layer, such as a photosensitive planographic printing plate, with a processing solution while conveying the photosensitive material, the photosensitive layer is brushed by a brushing member to promote the processing.
2. Prior Art
In a photosensitive planographic printing plate, images are formed when a photosensitive layer superposed on an aluminum plate, which is a support for the photosensitive planographic printing plate, is exposed to light so as to generate exposed portions and unexposed portions, and subsequently processing with a developer is performed to remove the unnecessary portions of the photosensitive layer.
During the processing with the developer, the photosensitive layer is brushed with a brush roller while the photosensitive planographic printing plate is immersed in the developer, so as to remove the unnecessary portions of the photosensitive layer. In this way, clear images can be formed.
In the prior art, a channel brush roller or a molton roller is used as the brush roller.
The channel brush roller can be made by planting bristles into a channel having a substantially xe2x80x9cUxe2x80x9d-shaped section and then winding this channel in a spiral configuration, tightly around the peripheral portion of a roller. The channel brush roller has excellent durability. However, the interval between the bristles in the spirally-wound channel is large in the axial direction of the brush roller, and thus brushing unevenness in the form of lines may be caused on the surface of the photosensitive planographic printing plate subjected to the brushing process. A complicated mechanism such as a mechanism for rotating the channel brush while the brush itself is being moved back and forth in the axial direction is therefore necessary.
In the channel brush roller, it is difficult to plant the bristles with uniform density and at a uniform angle. Moreover, when the channel is wound and configured as a roller, the bristles have to be made long to a certain extent in order to compensate for gaps between the wound channel portions adjacent to each other. As a result, the bristles cannot be made short and thus the bristles cannot be made firm. If the bristles are made thick so as to increase their firmness, the result is an unsatisfactory brush roller which easily generates brushing unevenness.
In the molton roller, the peripheral surface of the molton roller itself has a brushing function. Thus, brushing unevenness is somewhat better with the molton roller than with the channel brush roller. However, a completely satisfactory state cannot be attained. Besides, the molton roller has drawbacks in that it is not durable and its life span is short.
When pressure is applied to a part of the peripheral surface of the molton roller, that part deforms to generate a difference in the pressure with which the surface of a printing plate is rubbed. This causes brushing unevenness. Further, the material that is usually used in the molton roller wears quickly.
In the case of using, in particular, a photo-polymerizable layer (e.g., a photo-polymerizable layer of a photopolymer plate, which is one type of photosensitive planographic printing plate) as a photosensitive layer, it is necessary to rub the layer. Therefore, when the channel brush roller or the molton roller in the prior art is used, the above-mentioned inconvenience becomes very obvious. When the bristles of the brush roller are strongly applied to the photopolymerizable layer of the photopolymer plate to rub the photopolymer layer strongly, the tips of the bristles bend so that the unnecessary portions of the photopolymer layer cannot be satisfactorily removed. In other words, the original function of the brush roller cannot be attained.
Thus, as a means for overcoming the above-mentioned problems of the channel brush roller, Japanese Patent Application Laid-Open (JP-A) No. 3-96955 discloses a helical channel brush roller that is a modification of the above-mentioned channel brush roller. However, in the helical channel brush roller, the interval between channels cannot be made shorter. It is therefore necessary to perform the brushing process with a considerably increased rotation frequency. If the rotation frequency is increased, a burden is imposed on a bearing which supports the helical channel brush roller. As a result, the bearing wears away with the passage of time and this may cause uneven rotation. Further, this modification cannot overcome the unevenness of the density with which the bristles are planted into a channel.
As a means for overcoming the above-mentioned problems of the molton roller, Japanese Patent Application Laid-Open (JP-A) No. 10-48840 discloses bristles of the molton roller that are made of polypropylene. By this improvement, durability is made greater than molton rollers in the prior art but the drawback of brushing unevenness has not been overcome.
In the light of the above-mentioned situation, an object of the present invention is to provide a photosensitive material automatic-processing apparatus in which a roller can be used as a core member and the planting density of brushing-bristles that are provided on the peripheral surface of the roller can be made uniform, thereby overcoming brushing unevenness.
A first aspect of the present invention proposes an apparatus for processing photosensitive material, in which the photosensitive material is brushed by a brush member for promoting image; forming processing when it is transported through the apparatus, the brush comprising:
(a) a roller adapted for mounting in the apparatus so as to be rotatable about an axis generally transverse to a direction in which the photosensitive material is transported when being processed in the apparatus, the roller having a peripheral surface; and
(b) a brushing band having a substrate with bristles woven into the substrate, the brushing band being set into the peripheral surface of the roller.
According to the first aspect, the bristles for brushing can be made fine. Also, because the bristles are woven, it is possible for the bristles to be disposed at a pitch accurate to the xcexcm and at a set uniform density. Moreover, since the bristles have an appropriate rigidity, the brushing member can be applied to a photosensitive material that requires relatively strong rubbing.
In a second aspect of the present invention, the substrate apparatus is a knitted fabric.
In a third aspect of the present invention, the bristles comprise at least one material selected from the group consisting of natural fibers and artificial fibers, with each bristle having a thickness from 1 to 10,000 deniers, and a length from 1 to 35 mm, with the bristles arranged in the brushing band to have a density from 1000 to 225,000 deniers per square cm (preferably from 45,000 to 200,000 deniers per square cm) where the density is defined as average number of bristles per unit area multiplied by average thickness of the bristles.
In a fourth aspect of the present invention, a relationship exists between an average length, L, of the bristles in mm and average thickness, D, of the bristles in deniers, with 1xe2x89xa6Lxe2x89xa67.5xc3x97[log(D)+⅔].
In a fifth aspect of the present invention, the bristles comprise a metallic fiber, each metallic fiber having a diameter from 10 to 200 xcexcm and a length from 1 to 30 mm, with the bristles arranged in the brushing band to have a density from 0.05 to 7.0 mm2/cm2, where the density is defined as average number of bristles per cm2 multiplied by average cross sectional area of a bristle in mm2.
In a sixth aspect of the present invention, a relationship exists between an average length, L of the fibers in mm and average diameter of the fibers, R, in xcexcm, said relationship satisfies 1xe2x89xa6Lxe2x89xa6[(0.1R)+10].
In a seventh aspect of the present invention, the roller includes a groove defined in the peripheral surface of the roller for at least partially accommodating the brushing band therein, and a fixing member for fixing the brushing band in the groove.
According to the seventh aspect, the brushing band is at least partially fixed to the groove formed on the outer peripheral portion of the roller by means of the fixing member that is accommodated, together with the brushing band, in the groove. That is, the brushing band can be fixed to the outer peripheral portion of the roller without use of any adhesive agent.
Therefore, a problem where an adhesive agent permeates the bristles from the end of the brushing band and solidifies to cause the bristles to lose flexibility and thus damage a printing plate does not arise. Even if no adhesive agent is used at the time of setting the brushing band onto the outer peripheral portion of the roller, the winding of the band does not become loose and the band can be kept stably set onto the roller. Besides, since no adhesive agent is used, the complicated work of applying of an adhesive agent is not necessary and the brush member can be produced at a low cost.
In an eighth aspect of the present invention, the groove spirally extends along the peripheral surface of the roller.
In a ninth aspect of the present invention, the groove extends substantially parallel to the rotational axis of the roller when the roller is rotatably mounted in the apparatus.
In a tenth aspect of the present invention, the fixing member is a metallic wire.
In an eleventh aspect of the present invention, the fixing member is a resin piece or a metallic piece.